The motor i bought has 882 heads on it. The guy i bought it from, says he thinks he has some double humps, and will give them to me if he can find them.

Someone tell me the story on the two, and which i'd be better off with...Please?

silly me didnt search first.. :P

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882's flow OK but are prone to cracking
882's are big 76cc chamber ,if your engine was built for that size chamber then a smaller chamber may blow your compression out .( double hump 461 /462 /292's were 64cc ?)

http://www.hotrodders.com/forum/-705...nglepost4.html
http://www.hotrodders.com/forum/-705...glepost12.html
http://www.hotrodders.com/forum/-496...glepost13.html
http://forums.off-road.com/gm-standa...tml#post146980

http://www.jalopyjournal.com/forum/s...d.php?t=119815

 

well we're going back with flat tops, and maybe .030 over so i have no clue what the compression will be.

 

882s are not prone to cracking. whoever says otherwise is just parroting a lie they read somewhere. If you get your piston-to-head clearance to the ideal 0.040", then a 355 with flattops will be around 10.4:1 with double humps lightly milled, and that's way too much. With lightly milled 882s, you'll be closer to 9.3:1, and that's safe.

 

By what logic is this too much?

 

iron heads with slow burn chambers from the late 50s design theories? Too much. 10.4:1 is fine with AFRs or other modern aluminum heads, no doubt.
And don't even mention big cams, because those old heads don't flow well enough to benefit. If you cam them for power above 5500 rpm, you lose more low-end faster than you gain almost no top end.

 

Yeah, late model would be better fuelie's "double humps" are very soft not very good for our garbage pump gas these day's, If you do decide to use fuelie heads you should have hardened seats installed at least on the ex. side. 882' s don't flow very good but are hardened for unleaded fuels and no they don't seem to crack easily stay away from 624 casting's I can't say that I have seen any of them that are not cracked. All in all a set of vortec heads with a light bowl blend and screw in studs will yeild very nice power through the entire rpm band on a 350 with a hyd. cam just don't exceed .500 lift without major portwork.

 

Any reason why you cant go to a better head? The '882 head has a terrible combustion chamber. It will be less efficient then a newer head design, and more prone to detonation. If you want cheap power, I second the vortec castings. With a little work, they can really give good HP.

 

Well i'm just working with what i've got at hand. The vortecs are an option, i just dont want to have to put another 200 into a vortec specific intake that i cant ever use on anything else.

 

The "cracked" 882 heads were only the ones that have the exhaust crossover going to both center exhaust ports. The ones that have the exhaust crossover to a single exhaust port have a thicker casting. The 882 is still considered the best of the worst castings available.

By modern standards I wouldn't recommend the 882 or any double hump head. You're talking about using 40+ year old technology. Even the more modern vortec head will outperform those old castings. The cost of basic Dart Sportsman heads will be far less than what it takes to get a machine shop to properly modify those old castings to perform as well as modern castings do right out of the box.

 

Sportsman IIs have ultra mega super hyper crappy short turns. Better to get RHS or Dart or nearly anything else. The S2s were first designed back in the early '80s, and were heavily based on Mondello-ported double-humps. Sounds good on paper, but get the bare heads in your hands, compare them to any head designed after 2000, ( except Edelbrock, their short turns still sucked until about 2-3 years ago ) and you'll see the problems.

 

Well that's how they rolled in the late 60's early 70's when the double humps were still "new." I recall they worked pretty well. I mean the emissions were ****, but they made power.

 

Not really, no. Look at the best of them all, the '70 'vette LT-1. rated 370 horses at 6000 rpm, gross, with a huge solid roller cam, and 380 ft-lbs, with 11:1. Now go look in the swap stickies, in my best builds. That's a 9:1, hydraulic roller 350 with un-touched Vortecs, offering 401 horses at 5600 rpm, no need to go to 6000, and 428 ft-lbs. Plus the cam is small enough to pass an emissions test.
the old LT-1 is down 48 ft-lbs of peak torque, despite an extra 2 ratios of compression. That's not decent, that's sad.

 

Personally, I call it progress. They had bad heads and bad valve springs by today's standards, but the engineer's found the power. Frankly if our engines weren't better today, I'd be very disappointed.

 

blah blah blah...lookie hear...get the doublehumps and put um on with flat tops and run 93 pump gas and youll be FINE. if you got a 350 with flat tops you'll run a solid 10 to 1 compression(use thick headgaskets) torque will be awsome and horsepower depending on the cam you run will be between 300 and 440 horsepower. period

 

I'm going budget here. i mean, if i can get free double humps and get the local napa to clean them and install new seals for 80 bucks, then slap em on and still get decent hp i've got 80 dollars into it.. not 600 for the vortecs, and the 200 for the vortec specific intake and the 40 on the specific gaskets for the vortecs.

I'm probally just gonna go with the double humps or the heads off some late model pre-vortec 350